The present invention constitutes a specific, needed improvement over the machine tool disclosed in U.S. Pat. No. 3,609,838, also constitutes a specific variant upon the machine tool design of my earlier application Ser. No. 801,181.
As explained in my earlier application, it is quite desirable, in a machine tool of the type wherein a plurality of peripherally spaced pallets are carried on an angular annular rotatable gear, to have the pallets carried directly by the gear, rather than through a "spring pack" interposed between the pallet and the gear. In my earlier application, the gear was raised and lowered by means of support rollers or the like cooperable with cam recesses formed in the under surface of the gear itself. While this type of machine tool is prefectly feasible and has been commercially successful, the present invention provides a further improvement in the gear elevating and lowering mechanism and also in the mechanism for clamping each pallet at a machining location.
In both the prior art Wiest U.S. Pat. No. 3,609,838 an my earlier application, the same clamping structure was utilized, i.e. clamping was effected between a conical recess on the pallet itself and a conical head carried by clamping cylinders located at each machining station. The final location at the machining location is attained by interfitting engagement of these two conical surfaces.
Further, in my earlier invention, the pallet was connected to the gear through a simple "lost motion" connection, and the pallet could move relative to the gear as the pallet was being transported by the gear between machining locations.
An improved locating and clamping mechanism and the elimination of relative pallet-gear movement during transport would be desirable improvements upon my earlier invention.